A construction machine, particularly a large-sized hydraulic excavator or the like, is used, e.g., for excavation of each and rocks in a large work site. In general, such a hydraulic excavator is continuously operated for the purpose of increasing productivity. If there occurs an abnormality, it is required to stop the operation of the hydraulic excavator and repair it. Depending on the severity of the abnormality, the operation must be stopped for a long period. In that case, because production work with the hydraulic excavator is suspended, scheduling of a production plan must be changed.
To diagnose soundness of the hydraulic excavator with the view of avoiding that problem, it is required to detect information regarding the internal state, the abnormal state, etc. of the hydraulic excavator. In recent situations, the number of kinds of data to be detected has been increased with increasing complexity in structure of the hydraulic excavator (see, e.g., Patent Reference 1).
Patent Reference 1: JP,A 2002-301953